1. Field of the Invention
The present invention relates to magnetic tape drive equipment. More particularly, the present invention relates to apparatus for extracting the tape from the cassette and guiding it into engagement with the tape heads which are used to read the information from the tape.
2. The Prior Art
Mechanisms for inserting and ejecting magnetic tape cassettes from the devices in which they are utilized exist in the prior art. While these mechanisms often provide for the manual insertion of the tape cassette into the device, all such mechanisms known to the inventors utilize a motor drive for the purpose of assisting in the insertion and ejection of the tape cassette from the device once it has finished running. In such mechanisms, a power failure in the device makes the extraction of the cassette from the device difficult or impossible.
In addition, any mechanism for inserting and ejecting the cassettes must take into account the height of the tape drive hub spindles (approximately 0.30") used in the device to drive the tape reels contained within the cassettes, since the cassette must clear them when it is both inserted and ejected. The presence of the tape drive hub spindles also requires that the vertical motion of the cassette during insertion and ejection be free from any degree of lateral motion or tilt which would act to bind the cassette on the hub spindles and thus impede its motion.
Devices equipped with helical-scan heads include tape correction pins which are used to correct the orientation of the tape from the tilted plane caused by its engagement with the helical-scan head drum assembly to the vertical plane associated with the cassette. In such devices in the prior art which are known to the inventors, these pins are usually located within the tape puller roller blocks which are used to bring the tape into contact with the helical-scan head drum assembly. Because these pins are placed on the moveable tape puller roller blocks, they are more or less prone to misalignment caused by improper registration of the blocks with the drum assembly.
Prior art tape engagement devices are often exceedingly complex in order to provide the necessary timing for proper activation of all of the tape drive and engagement mechanisms. For example, a tape drive must have some lost motion in both a clockwise as well as in a counterclockwise direction, while at the same time other parts related to the tape drive and engagement mechanism must remain stationary. Accordingly, there is a need for a simplified tape drive which has lost motion in both a clockwise and a counterclockwise direction while at the same time enables other parts of the assembly to remain stationary.
Another problem in prior art devices is the need to maintain a precise timing relationship between the capstan arm pinch roller and the tape drive mechanism. Prior art devices fail to provide a simplified system for precise timing between the front capstan arm and the tape drive. This often results in uneven tension applied by the capstan arm roller against the tape which impairs the constant movement of the tape through the system and degrades sound quality.
Accordingly, there is a need for a simplified mechanism which allows the tape drive to have lost motion in both a clockwise as well as a counterclockwise direction while at the same time maintaining the constant movement of other parts related to the tape drive engagement system.
There is also a need for an improved capstan arm pinch mechanism which will maintain a constant timing relationship between the capstan arm and the drive means. Such an improved capstan arm mechanism advantageously should maintain a constant application of a precise amount of tension against a tape so that its movement through the system is not subject to deviation.